Rosa Maria Levandovski

Obesity and shift work: chronobiological aspects.

The present review has the objective of summarising chronobiological aspects of shift work and obesity. There was a systematic search in PubMed databases, using the following descriptors: shift work; obesity; biological clock. Shift work is extremely frequent in several services and industries, in order to systematise the needs for flexibility of the workforce, necessary to optimise productivity and business competitiveness. In developing countries, this population represents a considerable contingent workforce. Recently, studies showed that overweight and obesity are more prevalent in shift workers than day workers. In addition, the literature shows that shift workers seem to gain weight more often than those workers submitted to a usual work day. In conclusion, there is considerable epidemiological evidence that shift work is associated with increased risk for obesity, diabetes and CVD, perhaps as a result of physiological maladaptation to chronically sleeping and eating at abnormal circadian times. The impact of shift work on metabolism supports a possible pathway to the development of obesity and its co-morbities. The present review demonstrated the adverse cardiometabolic implications of circadian misalignment, as occurs chronically with shift workers.

Depression Scores Associate With Chronotype and Social Jetlag in a Rural Population

In public health, mood disorders are among the most important mental impairments. Patients with depressive episodes exhibit daily mood variations, abnormal patterns in sleep-wake behavior, and in the daily rhythms of several endocrine-metabolic parameters. Although the relationship between the sleep/circadian processes and mood disorders is poorly understood, clock-related therapies, such as light therapy, sleep deprivation, and rigid sleep schedules, have been shown to be effective treatments. Several studies investigated the relationship between circadian phenotype (chronotype) and depression. These focused mainly on urban populations and assessed diurnal preferences (Morningness-Eveningness score) rather than the actual timing of sleep and activity. Here, we used the Beck Depression Inventory (BDI) in an essentially rural population (N = 4051), and investigated its relation to circadian phenotype (chronotype and social jetlag), assessed with the Munich Chronotype Questionnaire (MCTQ). In our study design, we (i) normalized both chronotype and BDI scores for age and sex (MSFsas and BDIas, respectively); (ii) calculated individual social jetlag (misalignment of the biological and social time); and (iii) investigated the relationship between circadian phenotypes and BDI scores in a population homogeneous in respect to culture, socioeconomic factors, and daily light exposure. A 15.65% (N = 634) of the participants showed mild to severe depressive BDI scores. Late chronotypes had a higher BDIas than intermediate and early types, which was independent of whether or not the participants were smokers. Both chronotype and BDIas correlated positively with social jetlag. BDIas was significantly higher in subjects with >2 h of social jetlag than in the rest of the population—again independent of smoking status. We also compared chronotype and social jetlag distributions between BDI categories (no symptoms, minimal symptoms, and mild to severe symptoms of depression) separately for men and women and for four age groups; specifically in the age group 31–40 yrs, subjects with mild to severe BDI scores were significantly later chronotypes and suffered from higher social jetlag. Our results indicate that misalignment of circadian and social time may be a risk factor for developing depression, especially in 31- to 40-yr-olds. These relationships should be further investigated in longitudinal studies to reveal if reduction of social jetlag should be part of prevention strategies. (Author correspondence: karla.allebrandt@med.uni-muenchen.de)

Preoperative Anxiolytic Effect of Melatonin and Clonidine on Postoperative Pain and Morphine Consumption in Patients Undergoing Abdominal Hysterectomy: A Double-Blind, Randomized, Placebo-Controlled Study

UNLABELLED Recent evidence has demonstrated analgesic, anti-inflammatory, and anxiolytic properties of melatonin. Taking into account that higher anxiety makes the control of postoperative pain more difficult, one can hypothesize that melatonin anxiolytic and analgesic effects improve the control of postoperative pain. Thus, we conducted a randomized, double-blind, placebo-controlled study with 59 patients undergoing abdominal hysterectomy to test the hypothesis that melatonin is as effective as clonidine and that both are more effective than placebo in reducing postoperative pain. Additionally, we compared their anxiolytic effects on postoperative pain. Patients were randomly assigned to receive oral melatonin (5 mg) (n = 20), clonidine (100 microg) (n = 19), or placebo (n = 20) orally. In addition to primary outcomes of pain intensity and analgesic consumption, secondary outcome measures included postoperative state anxiety. In anxious patients 6 hours after surgery, the number of patients needed to be to prevent moderate to intense pain during the first 24 hours after surgery was 1.52 (95% CI, 1.14 to 6.02) and 1.64 (95% CI, 1.29 to 5.93), respectively, in the melatonin and clonidine groups compared with placebo. Also, the anxiolytic effect of melatonin and clonidine resulted in reduced postoperative morphine consumption by more than 30%. However, in the mildly anxious, it was not observed the treatment effect on pain. PERSPECTIVES The preoperative anxiolysis with melatonin or clonidine reduced postoperative pain and morphine consumption in patients undergoing abdominal hysterectomy. The effects these 2 drugs were equivalent and greater than with placebo.

Chronotype: a review of the advances, limits and applicability of the main instruments used in the literature to assess human phenotype.

The study of circadian typology differences has increased in the last few years. As a result, new instruments have been developed to estimate the individual circadian phase of temporal human behavior, also referred as chronotype. The current review was conducted to evaluate the differences among the questionnaires most frequently used to assess chronotype: the Morningness-Eveningness Questionnaire (MEQ), the Composite Scale of Morningness (CSM), and the Munich Chronotype Questionnaire (MCTQ). Each instrument evaluates a different aspect of chronotype. MEQ is considered to evaluate the phase preferences of individual behavior over a 24-hour day, while MCTQ measures the phase of sleep positions for both free and work days. CSM is similar to MEQ, but is more sensitive to measure shift work. The concept of chronotype has been used to refer to phase positions or phase preferences in the literature reviewed. Most of the time this is a consequence of different interpretations: it is not clear whether phase preferences are a direct manifestation of the individuals internal clock or a result of external cues, e.g., social interaction (including the alarm clock). Also, phase preferences are not uniform throughout life. Therefore, a single assessment, not taking age into consideration, will not accurately describe the sample. We suggest that MCTQ is the best instrument for investigators dealing with desynchronization and as an instrument for sleep phase. Conversely, if the goal is to assess characteristics that change under specific situations - chronotype -, the MEQ should be used.

Night eating patterns and chronotypes: A correlation with binge eating behaviors

This cross-sectional study examined the association between the morningness/eveningness dimension and eating patterns. The sample consists of 100 subjects who were screened at a nutrition clinic and was composed of 77% women; mean age was 39.5 (±11.7) years; and 66% were overweight. Significant bivariate correlations were found between the Morningness-Eveningness Questionnaire (MEQ) total score and the Binge Eating Scale (BES) and the Night Eating Questionnaire (NEQ). The NEQ and BES were also significantly correlated. Body mass index (BMI) was correlated with the NEQ and BES, but it was not a confounding variable as no associations were found between the MEQ and BMI. To control for potential multicollinearity effects among variables, we also used multivariate regression analysis in which the values of the correlation coefficients were adjusted. Only the BES remained statistically associated with the MEQ. In conclusion, these results suggest that the study of chronotype may be an important issue to be considered when characterizing disordered eating. This study serves as an impetus for examining circadian intake patterns in more detail between those with binge eating disorder (BED) and night eating syndrome (NES) to help discern these important nosological questions.

Morningness–eveningness, use of stimulants, and minor psychiatric disorders among undergraduate students

Morningness-eveningness dimension in humans have been indicated to influence social behavior and individual health. The aim of the present study was to investigate the association of the morningness-eveningness dimension with behavioral and health aspects in a sample of undergraduate students. We assessed demographic data; the Pittsburgh Sleep Quality Index was used to evaluate sleep quality; the Morningness/Eveningness Questionnaire to determine morningness-eveningness, and the Self-Reporting Questionnaire to assess minor psychiatric disorders. A total of 372 students (66.7% females), on average 21.6 years old, participated in this study. Among them, 92.2% did not smoke, 58.9% engaged in physical activities, and 19.7% were night-shift workers. In regard to morningness-eveningness, 55.9% of the participants were intermediate between evening (39.5%) and morning (4.6%) types. Poor sleep quality (OR = 1.89), minor psychiatric disorders (OR = 1.92), and tobacco consumption (OR = 3.65) predominated among evening types. Evening types were predominantly males (OR = 1.72). This study suggests that evening types are more vulnerable to sleep and psychiatric disturbances, and tend to smoke more than morning types.

Impact of preoperative anxiolytic on surgical site infection in patients undergoing abdominal hysterectomy.

BACKGROUND An increased anxiety may be associated with a higher risk of surgical site infection (SSI), but there is little objective data on the effect of preoperative anxiolytic interventions on SSI. To address this issue, we evaluated the effects of preoperative diazepam on postoperative SSI following abdominal hysterectomy. METHODS This randomized, double-blinded, placebo-controlled study included 130 patients, American Society of Anesthesiologist physical status 1 or 2. Patients were randomly assigned to receive either oral diazepam 10 mg (n = 65) or placebo (n = 65) the night before and 1 hour prior to surgery. The assessment instruments were the Visual Analogue Scale and the State-Trait Anxiety Inventory. SSI was diagnosed according to the criteria of the Centers for Disease Control and Prevention with standard follow-up of 30 days. RESULTS The relative risk (RR) was 1.79 (95% confidence interval [CI]: 1.31-2.43), and the number of patients that needed to be treated was 5.2 (95% CI: 2.74-50.76) to prevent 1 additional SSI. The RR for SSI in placebo-treated patients with high postoperative anxiety was 1.65 (95% CI: 1.07-2.56). CONCLUSION Diazepam-treated patients showed lower postoperative anxiety and lower incidence of SSI up to 30 days after surgery compared with placebo in patients undergoing abdominal hysterectomy.

Differences in circadian patterns between rural and urban populations: An epidemiological study in countryside

The physiological pattern of the sleep–wake cycle is influenced by external synchronizing agents such as light and social patterns, creating variations in each individual’s preferred active and sleep periods. Because of the demands of a 24-h working society, it may be imperative for many people to adapt their sleep patterns (physiologically) to their daily activities. Therefore, we analyzed the difference in sleep patterns and chronobiological parameters between an essentially rural farming and urban small-town populations. We studied 5942 subjects (women, 67.1%, N = 3985; mean age, 44.3 ± 13.1 years), from which the chronotype, circadian sleep pattern, and period of light exposure were collected using the Munich Chronotype Questionnaire (MCTQ). A structured questionnaire was also made for collection of social and demographic information. Compared with the urban population (N = 3427, 57.7%), the rural population (N = 2515, 42.3%) presented a more predominantly early sleep pattern, as determined by the mid-sleep phase (rural: 2.26 ± 1.16; urban: 3.15 ± 1.55; t-test, p < 0.001). We also found less social jetlag (rural: 0.32; urban: 0.55; Mann–Whitney U test, p < 0.001) and higher light-exposure (rural: 9.55 ± 2.31; urban: 8.46 ± 2.85; t test, p < 0.001) in the rural population. Additionally, the rural population presented a higher prevalence of psychiatric disorders (rural: 156, 6.20%; urban: 165, 4.80%; Chi-square, p < 0.05), and a lower prevalence of metabolic diseases (rural: 143, 5.70%; urban: 225, 6.60%; Chi-square, p < 0.05). The significant difference in sleep parameters, chronotype, and light exposure between groups remained after multivariate regression analysis (r2 = 0.41, F = 297.19, p < 0.001, β = 1.208). In this study, there was a significant difference between the rural and urban populations in natural light exposure and sleeping patterns. Because of agricultural work schedules, rural populations spend considerable time outside that is an obligation related to work schedules. Our results emphasize the idea that latitude may not be the main factor influencing individual circadian habits. Rather, circadian physiology adapts to differences in exposure to light (natural and artificial) as well as social and work schedules.

The effect of sunlight exposure on interleukin-6 levels in depressive and non-depressive subjects

BackgroundThe objective of this epidemiological study was to evaluate the effect of length of sunlight exposure on interleukin 6 (IL-6) levels in depressive and non-depressive subjects.MethodsThis was a cross-sectional study with 154 subjects (54 males, mean age: 43.5 ± 12.8 years) who were living in a rural area in south Brazil. Chronobiological and light parameters were assessed using the Munich Chronotype Questionnaire. Sleep quality was evaluated using the Pittsburgh Sleep Quality Index. Depressive symptoms were assessed with the Beck Depression Inventory. Plasma levels of inflammatory cytokines (IL-2, IL-4, IL-6, IL-10, tumor necrosis factor-α, and interferon) were collected during the daytime and measured.ResultsIL-6 levels showed a positive correlation with light exposure (r = 0.257; p < 0.001) and a negative correlation with the mid-sleep phase on work-free days (r = -0.177; p = 0.028). Multiple linear regression analysis showed that only the length of light exposure was an independent factor for predicting IL-6 levels (ß = 0.26; p = 0.002). In non-depressed subjects, exposure to a different intensity of light did not affect IL-6 levels (t = -1.6; p = 0.1). However, when the two depressive groups with low and high light exposure were compared, the low light exposure group had lower levels of IL-6 compared with the high light exposure group (t = -2.19 and p = 0.0037).ConclusionsThe amount of time that participants are exposed to sunlight is directly related to their IL-6 levels. Additionally, depressed subjects differ in their IL-6 levels if they are exposed to light for differing amounts of time.

The influence of school time on sleep patterns of children and adolescents.

OBJECTIVE This epidemiological study evaluated the impact of school time on sleep parameters of children and adolescents. METHODS This cross-sectional study involved 639 elementary and high school students (mean age 13.03 years, range 8-18, 58.5% female) from the south of Brazil. Participants answered the Morningness-Eveningness Questionnaire (MEQ), and were asked about their sleeping habits on weekdays and weekends. Sleep deficit was defined as the difference between sleep duration on weekdays and weekends. RESULTS The morning-school-time students presented significantly higher age, bedtime and wake up differences, sleep deficits, and social jetlag. The sleep deficit presented by girls was greater than that observed in boys of the same age. The difference between weekday and weekend waking times was also significantly greater in girls than in boys aged 13-18 years. Sleep deficit was significantly positively correlated with age and differences in wake up times, and significantly negatively correlated with MEQ scores, social jetlag, difference between weekday and weekend bedtimes, midpoint of sleep on weekends, and midpoint of sleep on weekends corrected for sleep deficit. A step-by-step multivariate logistic regression identified social jetlag, the difference between waking times on weekdays and weekends, and the midpoint of sleep on weekends as significant predictors of sleep deficit (Adjusted R(2) = 0.95; F = 1606.87; p <0.001). CONCLUSION The results showed that school time influences the sleep parameters. The association of school schedules and physiological factors influence the sleep/wake cycle.